What is Circular motion: Definition and 1000 Discussions

In physics, circular motion is a movement of an object along the circumference of a circle or rotation along a circular path. It can be uniform, with constant angular rate of rotation and constant speed, or non-uniform with a changing rate of rotation. The rotation around a fixed axis of a three-dimensional body involves circular motion of its parts. The equations of motion describe the movement of the center of mass of a body. In circular motion, the distance between the body and a fixed point on the surface remains the same.
Examples of circular motion include: an artificial satellite orbiting the Earth at a constant height, a ceiling fan's blades rotating around a hub, a stone which is tied to a rope and is being swung in circles, a car turning through a curve in a race track, an electron moving perpendicular to a uniform magnetic field, and a gear turning inside a mechanism.
Since the object's velocity vector is constantly changing direction, the moving object is undergoing acceleration by a centripetal force in the direction of the center of rotation. Without this acceleration, the object would move in a straight line, according to Newton's laws of motion.

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  1. L

    Circular Motion: Coefficient of Static Friction, u=0.2, Angular Speed, w

    The coefficient of static friction between the slider and the rod is u=0.2. The inclined rod rotates about a vertical axis AB with a constant angular speed, w, as shown in Figure. At the instant shown, the slider is positioned at 0.6 m from B. (i) What is the acceleration of slider P if it does...
  2. S

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    while using equations of circular motion why do we need to express all angles in radians?
  3. P

    How is tangential accleration zero in uniform circular motion?

    How is tangential accleration zero in uniform circular motion?? Homework Statement the magnitude of tangential velocity is same but the directions are different..so how can the tangential acceleration be zero?? Homework Equations The Attempt at a Solution
  4. M

    Circular motion related to 1 dimension?

    Alright, I have wondered this for a very long time and probably thought about it for longer than I should have but the more I think about it, the more I seem to be correct and the more frustrating it is to talk to people about it... Anyways, I'm sure everyone has heard of the saying "lefty...
  5. A

    Laws of motion and circular motion

    Homework Statement [PLAIN]http://img687.imageshack.us/img687/5055/imagelrl.jpg Homework Equations Static friction = (9.81sin60 x 0.2)N Centripetal force = mr(w)² The Attempt at a Solution I am only abl to get part (i), need hints for part (ii) and (iii). Thanks in advanced
  6. B

    Dynamics of uniform circular motion

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  7. B

    Uniform circular motion, trapeze artists problem

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  8. B

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  9. A

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  10. R

    Non Uniform Circular Motion w/ Calculus and Vectors

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  11. K

    Circular Motion and friction problem.

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  12. B

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  13. F

    What is the tension in the string for circular motion of keys?

    Keys with a combined mass of 0.100 kg are attached to a 0.25m long string and swung in a circle in the vertical plane. a) What is the slowest speed that the keys can swing and still maintain a circular path? b) What is the tension in the string at the bottom of the circle? for part a, I...
  14. J

    I with this Uniform circular motion problem

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  15. S

    Zero Normal force during uniform circular motion?

    I am learning uniform circular motion and the question says: A child on a sled comes flying over the crest of a small hill. His sled does not leave the ground but he feels the normal force between his chest and the sled decrease as he goes over the hill. Explain. Now, I know that normal force...
  16. M

    Going Loopy (vertical circular motion)

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  17. G

    Calculating Centripetal Acceleration for a Frisbee in Circular Motion

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  18. E

    Circular motion, find V when only given m and r

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  19. Femme_physics

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  20. J

    Question on uniform circular motion

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  21. S

    Another Circular motion Question

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  22. N

    Maximizing Acceleration in Circular Motion: Understanding Loop Dynamics

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  23. I

    Some circular motion questions

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  24. P

    Circular Motion of a horizontal disc Problem

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  25. P

    Velocity Vectors in Circular Motion: Understanding Acceleration

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  26. S

    Mastering Circular Motion: Tips for Solving Conservation of Energy Problems

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  27. Femme_physics

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  28. C

    Question - Circular motion amusement park physics

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  29. K

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  30. K

    Loop related to Circular motion

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  31. O

    Friction on bicycle wheels in uniform circular motion

    On pedaling a bicycle along a straight line, the friction act forward on the rear wheel and act backward on the front wheel. If I turn its handlebar so that the front wheel is at a certain angle (say theta) and pedal it in uniform circular motion, what would be the direction of the friction...
  32. Femme_physics

    Circular motion formulas, what does the angle without the function mean?

    http://img864.imageshack.us/img864/9467/tnua.jpg I see an angle without a trigonometric function (delta theta - at the left side equations). I've never seen it before in a formula, and am not sure how to use it. Can anyone tell me how? Do I just translate degrees to radians and just plug the...
  33. M

    Non-Uniform Circular Motion - Find Change in time

    Homework Statement Find the time it takes for a particle initially at rest to travel around a circle with acceleration \ddot{\theta} = -3 \cos{\theta} to travel 1/4 of the circle.2. The attempt at a solution \int_{0}^{{\frac{\pi}{2}}}-3 \cos{\theta} Am I doing this right?
  34. Femme_physics

    Uniform circular motion with a pendulum

    Homework Statement http://img685.imageshack.us/img685/9250/drawingmo.jpg In the drawing is depicted a pendulum hammer of an impact device (in both projections). The hammer is made out of shaft AB which upon it is held pendulum OM. At point M of the pendulum is a hammer. According to...
  35. Femme_physics

    Uniform circular motion problem

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  36. Femme_physics

    Uniform circular motion - simple problem

    Homework Statement A girl is running around a circular fountain with a diameter of 6.5m. If it takes her 72 seconds to run all the way around, what's her angular speed? The Attempt at a Solution I appear to be getting a wrong answer: (look only at the thick black marker)...
  37. P

    Very Simple Uniform Circular Motion Derivation

    Homework Statement This is a very easy derivation (I think), I forgot how to do it though. How do you derive a = \frac{4\pi^2R}{T^2} or a = 4\pi^2Rf^2? Homework Equations The Attempt at a Solution They both mean the same thing since T is Inverse Frequency but I don't understand how...
  38. F

    Circular motion of key swing

    Keys with a combined mass of 0.100 kg are attached to a 0.25m long string and swung in a circle in the vertical plane. a) What is the slowest speed that the keys can swing and still maintain a circular path? b) What is the tension in the string at the bottom of the circle?
  39. F

    Bus Circular Motion: Calculating Minimum Friction for Laptop Stability

    A bus passenger has her laptop sitting on the flat seat beside her as the bus, traveling at 10.0 m/s, goes around a turn with a radius of 25.0 m. what minimum coefficient of static friction in necessary to keep the laptop from sliding?
  40. U

    Mass wraps around rod in circular motion

    Homework Statement A string attached to the center of a rod with radius R has a mass attached at the other end, moving with speed v0. Because of acceleration due to gravity the mass moves down while undergoing circular motion, causing the string to wrap around the rod. Find an expression for...
  41. K

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  42. P

    No Work Done during Circular Motion

    Hi guys, :smile: Work Done = Force x Distance x cos of Theta - the angle between the Force and the Displacement Vector / direction of motion In Circular motion I know the force but I am given velocity. In order to prove that no work is done is it correct to say the following: If we have two...
  43. K

    Please help, derivation of a=v^2/r of the circular motion using calculus

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  44. AlexChandler

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  45. M

    What are the forces involved in circular motion on a rotating pole?

    Homework Statement 17. A 100 g bead is free to slide along an 80 cm long piece of string ABC. The ends of the string are attached to a vertical pole at A and C, which are 40 cm apart. When the pole is rotated about its axis, AB becomes horizontal. a. Find the tension in the string. b...
  46. K

    Circular motion (conical pendulum)

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  47. S

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  48. M

    Banked Circular Motion with Static Friction

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  49. P

    Circular Motion: Understanding Centripetal Force

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  50. P

    Circular Motion and Linear Speed

    Hi, Points P and Q are at distances R and 2R respectively from the centre X of a disc The disc is rotating about an axis through X, normal to the plane of the disc. Point P has linear speed v and centripetal acceleration a. Which one of the following is correct for point Q? Linear Speed...
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